In recent years, the performance of portable electronic apparatuses such as a mobile phone, a personal computer (PC), and a personal digital assistant (PDA) has been remarkably enhanced, and a portable electronic apparatus provided with a camera module as an imaging function has been common. In such a portable electronic apparatus, a lens in the camera module is moved in an optical axis direction thereof to perform focusing and zooming.
Conventionally, the lens in the camera module is generally moved by a method using a voice coil motor, a stepping motor, or the like, as a drive unit. On the other hand, recently, an apparatus using a predetermined actuator element as a drive unit has been developed from the viewpoints of miniaturization. Examples of such an actuator element may include a polymer actuator element (see Patent Literature 1). For example, the polymer actuator element has an ion conductive macromolecular layer (hereinafter simply referred to as a macromolecular layer) disposed between a pair of electrodes. In the polymer actuator element, when an electric field is applied to the electrodes, ions move in the macromolecular layer to cause displacement. Therefore, the operation characteristics of the polymer actuator element such as a displacement amount and a generative force largely depend on a conductive environment of the ions. A polymer element is used as the polymer actuator element, as described above. In addition, the polymer element is also used for a polymer sensor element or an electric double layer capacitor.
For example, an ion exchange resin material is used for at least one of an electrode and a macromolecular layer in the polymer element. When the density of functional group in the ion exchange resin material is increased, that is, when the ion exchange capacity is increased, the ion conductivity of the polymer element is improved.